AN MU-2B ACFT WITH GARRETT ENGINES TPE 331-6-252M LOSES OIL PRESSURE AND REQUIRED MANUAL SHUTDOWN FOLLOWED BY A SAFE LANDING.

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IFR AT FL210 WHEN I NOTICED R ENG AUTO LIGHT CAME ON AT SAME TIME OIL PRESSURE DROPPED. MANUAL SHUTDOWN OF ENG FOLLOWED WITH SAFE LNDG AT ZZZ. INSPECTION OF ENG SHOWED SCAVENGER PUMP LINE HAD PULLED THE THREADS OUT OF THE DIAPHRAGM. THIS CAUSED DAMAGE TO THE MAIN JOURNAL BEARING IN THE GEAR BOX. ENG TYPE GARRETT TPE 331-6-252M. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED THE CAUSE OF THE OIL PRESSURE DROP WAS DUE TO THE GEAR CASE OIL SCAVENGE PICK-UP LINE THREADS WORKING IN THE THREADED PORTION OF THE MAGNESIUM DIAPHRAGM. THIS WEAR AND LOOSENESS AT THE THREADED END ALLOWED THE OIL TO LEAK PAST THE OIL PICK-UP LINE CAUSING THE SUDDEN LOSS OF OIL PRESSURE. REPORTER HAS HEARD THERE MAY BE A SERVICE BULLETIN TO PLUG THE CURRENT POSITION OF THE THREADED PICK-UP LINE TO THE MAGNESIUM DIAPHRAGM WITH A STRONGER MATERIAL. THIS PLUG WOULD THEN BE RE-DRILLED AND THREADED TO ALLOW FOR A MORE SECURE CONNECTION OF THE SCAVENGE LINE TO THE DIAPHRAGM. REPORTER ALSO NOTES HE BELIEVES THE MITSUBISHI MU-2B HAS BEEN GIVEN A BAD RAP REGARDING THE ACFT'S ACCIDENT RECORD; AND THAT HE WOULD MUCH PREFER TO BE IN THE MU-2B IF HE WERE TO LOSE BOTH ENGINES IN-FLIGHT DUE TO THE BETTER CONTROLLABILITY OF THIS ACFT.